If I have a force, say 24 kg/cm what would that equate to at 2cm? I would like to know the formulae for calculating this.
For example. If a motor can hold an object of 24kg at 1cm from its pivot point, what is it cable of holding at 5cm? And how is it calculated?

1 Answer
1

The units you mean are probably kg*cm (sometimes written kg.cm in robotics). Your original specification of 24 kgcm is a torque and not a force. The difference in practice is that, as the units imply, your resulting force at a point a distance from the "pivot point" decreases by the distance. So 24 kg*cm means that it can hold 24 kg at 1 cm or 12 kg at 2 cm etc.

Notice that strictly speaking kg is not a standard unit of force in physics since the force of gravity on a kilogram varies. In robotics, this seems to be the standard unit of servo torque though.

That's not what those units mean! 10 kg/cm would mean 10 kg at one cm, 20 kg at 2 cm, etc. (Compare with 60 miles/hour: 60 miles in 1 hour, 120 miles in 2 hours, etc.). But anyway, kg/cm don't seem to be the correct units here -- certainly, those aren't anything like the units of a force! I think C Earnest is right that what's being talked about here is really a torque, although it's hard to tell for sure. Torque comes in units of force times distance, not force per distance (N m vs. N/m). If what's being specified is a torque, then it does scale as you said: 2x the distance, 1/2 the force.
–
Ted BunnMay 29 '11 at 19:28

@Ted: ah sorry, both the OP and me must have misread; in robotics, the torque is specified in kgcm and not kg/cm :) I'll just remove the / sign from the post.. i've seen that servo spec so many times I just didn't notice the extra slash..
–
BjornWMay 29 '11 at 19:46

I was indeed refering to a torque. And have researched some more and discovered the lifting capability at 3cm would equal 8kg. (24/3=8) I believed the problem to be more complicated than it was. The only complicated part for me is factoring the weight of the lever itself. Thanks for all the help guys.
–
Mark WJun 1 '11 at 12:30